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Lecture 04, Wed 04/06

Wed Section: Happy Cows, jpa01, jpa02


Use #help-lecture-discussion

During lecture and section, if you need help with anything, please use the #help-lecture-discussion channel. We use this as a “help queue” to try to make sure that we get to all of the questions asked in the order in which they were posted.

Start Playing Happy Cows

Last quarter (W22), the students in CMPSC 156 worked on two applications:

Last year’s CHEM 123 class used an older version of the game written in a different web framework.

So, we are going to actually play the game for a couple of weeks.

About the game

You can check on your cows once a day.

How do I join the game?

Joining the game will count as a participation activity, P04.

  1. Navigate to:
  2. There is a shared username and password to get to the next screen; it will be shared on the slack in the #happycows-game channel. Please keep these shared credentials confidential within student in CMPSC 156 S22.
  3. Once you are past that screen, you’ll be asked to login with an OAuth username/password; you can use your UCSB email here.
  4. You should then see this page:


    Each of the “Commons” listed on the right hand side of the screen is one instance of the game.

    Please click where it says “Join Commons” beside two of the commons:

    • Everyone join the one called: cs156-s22
    • Everyone also join the one corresponding to their discussion section, either cs156-s22-4pm, cs156-s22-5pm or cs156-s22-6pm.
    • Please do not join any other game.

    The different games have different parameter settings for the price of a cow, the price of milk, and the number of players. We are hoping to learn about how these different parameter values affect game play, and game performance.

  5. Once you join a commons, the games you have joined will appear on the left hand column, like this:


    You can click the “Select” button to visit any of the commons (farms). When you visit a farm, look to see how much money you have and decide whether you want to buy any new cows or not:


    This is what it looks like after one day; I started with $1000 and purchased nine cows. That left me with $100. Then, after one day, I had earned $18 additional dollars; $2 for each of my nine cows. At this point, the cows are all in good health, it would appear. But perhaps as more cows are purchased, that may change; we’ll see!

    Also: the price of a cow may be different for each of the different sections; and we may change the prices over time.

Once you’ve joined the games for both your section and for the class as a whole, please make a post on your team channel on Slack indicating that you joined the game. Then you can turn to working on jpa01, or jpa02.

Working on jpa01 and jpa02

If you have questions about either of these, use #help-lecture-discussion.

You may also want to check #help-jpa00, #help-jpa01, and #help-jpa02 to see if there is any new information that may be helpful to you.